Horizontal metal extrusion presses are normally provided with a press frame formed by a cylinder plate, a counter plate, and at least four tie rods therebetween. It is significant for compact construction that the tie rods act as guides for the support holder and the movable plate which are shiftable in the press frame along the press axis (German patent 2,366,117). Such direct guiding on the tie rods allows one to dispense with a base frame functioning as a guide (German patent 644,174, German published application 2,003,244).
The support of the support holder and also of the movable plate is usually on support faces that are set at an angle so that their extension cuts the press axis or lies near the press axis, that is they point toward the press axis to ensure a centered position of the holder and the ram that will not be influenced by thermal expansion caused by temperature changes. In order to centrally position the holder and the ram on the press axis supports are arranged with a base frame supporting the guides for the support holder and the movable plate between the guides and the base frame, these supports being adjustable horizontally on the base frame perpendicular to the press axis and being vertically adjustable relative to the guides (German patent 644,174).
When dispensing with the base frame acting as guide frame and forming the tie rods as guides for the support holder and the movable plate, the supports must be eliminated and the adjusters must be arranged to be effective perpendicularly to the support surfaces oriented on the press axis in the support holder and movable plate, as this is done in a support holder guided by a press frame in German 1,452,264, and also in an extrusion press provided with a base frame formed as a guide frame as in German published application 2,003,244. This arrangement of the adjusters perpendicular to the support surfaces oriented on the press axis has the disadvantage that the adjustment always works out to vertical and horizontal components that must be compensated for by a displacement of the slide shoe of the adjuster riding on the support surface transverse to the displacement direction of the support holder and movable plate. Actuation of the adjusters is first done in setting up the extrusion press when the support holder and movable plate are at rest so that as a result of friction between the slide shoes and the support surfaces an offset either does not take place at all or only somewhat on displacement of the holder or of the movable plate, thereby making adjustment of the extrusion press more difficult.
When the extrusion press is calibrated only when it is warmed up, later temperature changes are lost along with the heat expansions which arrangement of the support surfaces for the support holder and movable plate relative to the press axis are intended to correct. As a result this arrangement is to be maintained. The press frame formed of cylinder plate, counter plate, and tie rods therebetween undergoes an elastic deformation such that the cylinder plate and counter plate bow outward and the tie rods bow inward, although this is minimized but not eliminated by the considerable rigidity of the cylinder plate and counter plate. Since the elimination of a base frame forming a guide frame results in the guiding of the support holder and the movable plate by the tie rods, the arrangement of the support surfaces on the tie rods oriented to the press axis is necessary.